Preparation of poly (acrylic acid) microgels by alcohol type cross-linkers and a comparison with other cross-linking methods

Kohestanian, M ; Sharif University of Technology | 2021

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  1. Type of Document: Article
  2. DOI: 10.1007/s00289-021-03878-5
  3. Publisher: Springer Science and Business Media Deutschland GmbH , 2021
  4. Abstract:
  5. Herein, poly (acrylic acid) (PAA) microgels were synthesized via alcohol type cross-linked by a free radical precipitation polymerization approach. At the first time, 1,6-hexanediol (1–6 diol), trimethylolpropane (TMP), and pentaerythritol (PEN) were selected as multifunctional cross- linking agent to synthesize cross-linked poly(acrylic acid) microgels. Alcohol type cross-linking agents can connect the PAA chains. The cross-linking reaction takes place due to reaction between hydroxyl groups of various cross-linkers and carboxyl groups of PAA chains. All of the hydroxyl groups do not participate in the reaction with acid groups of polymer chains through the polymerization stage; therefore, unreacted hydroxyl groups will react through sample drying (post-curing stage). The influence of cross-linker functionality and its concentration on various properties like swelling capacity, gel content, Tg (glass transition temperature), and rheological behavior were examined. The PAA microgels prepared via this cross-linking approach were compared to properties of microgels synthesized by epoxy type and vinyl type cross-linking agents in the previous studies. As a result, synthesized microgels via novel mechanisms have higher properties (for example, rheological and thermal properties) than that of PAA microgels prepared via the conventional mechanism. These behaviors can be due to decreasing Mc¯ (average molecular weight of two successive cross-links) in the polymeric network by utilizing new cross-linkers. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature
  6. Keywords:
  7. Carboxylic acids ; Curing ; Free radical polymerization ; Free radicals ; Gels ; Glass transition ; Swelling ; Average molecular weight ; Cross linking agents ; Crosslinking reaction ; Poly(acrylic acid ) ; Polymeric networks ; Precipitation polymerizations ; Rheological behaviors ; Swelling capacities ; Crosslinking
  8. Source: Polymer Bulletin ; 2021 ; 01700839 (ISSN)
  9. URL: https://link.springer.com/article/10.1007/s00289-021-03878-5